Alternate-current motor.



v A. FYNN. ALTERNATE CURRENT MOTOR.

APPLICATION FILED JUNE 12,1911.

. Patented NOV. 25, 1913.

INVENTOR Valre A.Fy1m

I ATTORNEY I WITNESSES: LI .mcwL

able conditions with but small lighter,

trunnion szmq, or LONDON, EuoLANp.

MQTOR.

Applipation filed iune rip M all 'w/Eom 2'5 may concern:

Be 11*" known that Z, ii Arjuna Ari-lino subject or the King England, st London, Ro land, have inv tsin new and us ful Alternate w, tor, of wine following, is soon olesr, wind 6 description as Willq ny in the art to which us so who and use the some, 1' once Doing lied to the accompanying lw ings, storming of. this specification.

My invention relates to alternate current motors either of single or polyphase tyne, but g1: 'ticulnrly opplionble to the fits objects to enable such mooliines to bestnrtcd with a, powerful t rqu per nzupere hut rithout the use of slip-rings or the like and to operated under favorslip at load. In order to achieve these oblin'ye devised an induced or secon-- {usually the rot r) of the novel roost;

ens

"ull

motion hsremalter set forth. In the prefufrred form my invention 1 make use in conjunction with he si -id seco ary anemia-er oi sli'isld or shields adapted to il'ilQEK-NIQ the power toot-or, tog QYQli BK l 0 naoity and the efiisiency n motor-r These shields to avlr l r in duction shields, or rent inrluotive en end windings of t d the secondary members and consist of son c form of eleotrically short-circuiited Winding or its. equivalent. I Indcscribing my invention 1 All refer to the sounpenying dingrammntio drawings in whicl1- Figure 1 llion/s one form of my improved motor in section; Fig. 2 is a View of joint of the second member adapted to op erste with the or shown in l3 1 or-in l 3, and furtncr illustrating the relative positions of the lauiinstions and windings on said second j i'nlier. lg, 3 shows n stationary form'of snield on the stator or primary member or my improved motor and is adopted for cooperation with the motor shown in Fig. 4 illustrates an end view of the rings sliortrircuiting the main sonirrelwage bars 15 and indicates that the lJfil'S 14 forming the auxiliary squirrel-cage insulated from the rings 8 and. 9.

Referring to Figs. 1 and 2 the stator,

Specification of Letters latent.

3, they Fatented Nov, 25, 1913. 1911. serial no. 32,553.

luniinstions 2 held in the frame 1 are provided with any desired or convenient prinngr Winding or windings indicated at 3. The rotor is mounted as usual on a shaft 7, but isprovidod with three groups of laminstions 4, 5, 6, of which 5 has approximately the same width as the stator lnminzv tions 2 and so arranged as to revolve wit in 2. This group of lnini'na'tions 5 is provided with Winding having bars 15 connefited to the end-1-ings 8 and 9. The I'Oturlnmination groups l and 6 are arranged at each side of the group 5 and carry an ordinary squirr -case ind ng h ving bars 14 c nnec ed to the end-rings ill and 11. These bars l4 pass tl rougl'; all the rotor laminations but are insuluted from the end rings 8 and 9. Shields 12 and 13 preferably of high conduptiyity metal are proyided at each end of the nmchine; they are supported on the shaft 7 and can slide along some until inserted between the groups of rotor lzuninm tions land 6 and the Siatorvwinding or w n ings 3 w i h h y then sep rate from he ro r l inetion 4; and 6. These shi ld pa e allow d o revolve with the shaft or they re ain stationery Whi the shaft revolves,-l nrefcr the latter arrangement; it is quite immaterial Whether il ese shields are suyported from the shaft or row the frame oftlie motor, whether they are movable or stationary and in the form of drums as in Fig. 1 or of windings e n ig- I ny c s they should be of low ohmic resistance. If movable god of a form such as is shown in Fig. 1 they must be capable of being introduced at will between the stator end-windings and the secondary member. stationary winding or windings, as in Fig.

must be capable of being short-circnited.

In order tostnrt such a motor it is only necessary to connect the stator, Whether Wound for polyphase, split-phase or any other mode of operation, tothe mains and allow the rotor to come up to speed. After a sufficient speed has been reached the shields 12, 13 are gradually or suddenly pushed home between the stator end Windings 3 and those ginrts 4, 6, of the rotor laminations which project beyond the stator loniinatious 2.

I prefer to make the squirrelloge em- If in the form of u:

bracing all the rotor laminations of higher ohmic resistance than the squirrel-cage embracing only part of the rotor laminations.

I believe the mode of operation of this .reactance will be due to the groups of rotor li'uninations l and 6 placed in close proximity to the end windings or connections of the stator windings. At starting the apparent reluctance of the group of rotor laminations 5 will naturally be very great owing to the screening effect of the low resistance squirrelcage which it carries; the leakage lield surrounding the end windings will consequently tend to be great and the presence of the laminations 4L and (3 will greatly incr aise this tendency. Under normal running conditions the apparent reluctance oi the group 5 will be considerably reduced and the leakage field surrounding the end windings will diminish very materially even if the groups of laminations 41 and 6 be not removed. The increased rcactance of the system at starting will obviouslyreduce the current taken by the motor at starting, on the other hand the torque will be increased because the currents induced by the leakage fields in the high resistance squirrel-cage, which embraces all the rotor laminations are nearly in phase with those fluxes with which they producevtorque. Because the high resistance squirrel-cage bars thread all the ro tor laminations they are placed in a position to produce torque with all the .tluxes threading the rotor laminations, therefore also with the comparatively large fluxes threading the group of laminations 5. As the machine increases its speed so does the effect of the high resistance squirrel cage winding diminish while the torque producing qualities of the low resistance squirrel cage increase rapidly and in a manner now well understood. It is quite feasible to operate the machine without further change but I prefer at some time during the starting period to introduce the shields 12, 13 lot-tween the stator end windings and the auxiliary groups of rotor laminations until said shields occupy positions as dotted in Fi g. 1. When in such a position said shields serve two purposes. They first reduce the leakage lield surrounding the stator end windings whereby the overload capacity and the power factor of the motor are increased and they also reduce the reactance of the high resistance squirrel-cage whereby the overload capacity, the etiiciency and the 1 ,ovaese power factor 01"? the machine are also improved.

It is, of course, not necessary to make use oi": both auxiliary groups of rotor laminations 4 and 6. One only of these may be used.

The shields shown in Fig. 1 are in the term of: copper drums and therefore are always ready to act as shields as long as they are located between the stator end windings and the auxiliary rotor laminat'ions. In Fig. 3 are shown two shields in the form of squirrel cage windings. The

bars 16 and 17 are always connected to the connectors 18 and 19 respectively but the connectors 20 and 21 may be connected to or discminectcd from the two groups bars by means of the switches 22 and 23 respectively. As long as the switches 22 and 23 are open the squirrel-cage windings on the stator are inoperative and produce no screening or shielding etl'ect. hen said switches are closed the squirrel cage windings of Fig. 3 are as effective as the drums 12, 13 of Fig. 1, when in the dotted positions 14:. When using stationary shields in the form of windings I leave these windings open at starting and short-circuit them after a sutlicient speed has been reached.

llaving fully described my invention, what I claim as new and desire to secure by Let ters latent oi the United States, is:

1. In an alternating current motor, the combination with an inducing member having a group oi laminations and windings partly embedded therein and partly projecting beyond said laminations, of an induced member having a plurality of grou s of laminations, one of said groups being 0" substantially the same width as the laminations of the inducing member and in line therewith, a winding embracing said group only, and a second winding on the induced member embracing a plurality of groups of laminations and in inductive relation with projecting portions of the inducing windings.

2. 111 an alternating current motor, the combination with a laminated inducing member, of an induced member of greater width than the inducing member and pro vided with a plurality of groups of laminations, one. of said groups being of substantially the same width as the laminations of the inducing member and in line therewith, a permanently short-circuited winding embracing said group only and a second Winding on the induced member of higher resistance than the first and embracing a plurality of groups of laminations.

3. In an alternating current motor, the combination with an inducing member, of an induced member provided with a main and two auxiliary groups of laminations, a winding embracing the main group only and a second winding of hi her resistance than the first and embracing l mth the main and the auxiliary groups of laminations.

.4. In an alternating current motor, the combination with an inducing member, of an induced member provided with amain and an auxiliary group of laminations, a winding embracing the main group only, and a second windingof higher resistance than the first embracing both the main and auxiliary groups of laminations.

5. In an alternating current motor, the combination with an inducing member, of an induced member provided with a main and an auxiliary group of lamimations, a winding embracing the main group only, a second winding embracing both the main and aux-- iliary groups of laminations, and means for varying the reactance of the second winding.

6. In analternating current motor, the combination with an inducing member, of an induced member provided with a main and an auxiliary group of laminations, a winding embracing the main group only, a second winding embracing both the main and auxiliary groups of laminations, and a shield for the auxiliary group of laminations.

7. In an alternating current motor, the combination with an inducing member having an inducing winding,- of an induced member provided with a main and an auxiliary group of laminations, a winding embracing the main group only, a second winding embracing both the main and auxiliary groups of laminations, and an induction shield or screen between the end windin of the inducing member and the auxi iary group of laminations.

8. In an alternating current motor, the combination with an inducing member having an inducing Winding, of an induced member provided with a main and an auxiliary group of laminations, a winding embracing the main group only, a second winding embracing both the main and auxiliary groups of laminations, an auxiliary Winding between the end windings of the inducing member and the auxiliary group of laminations, and means for short-circuiting said auxiliary Winding.

In testimony whereof, I have hereunto set my hand and afiixed my seal in the presence of the two subscribing Witnesses.

VALERE ALFRED'FYNN. [1 5.] Witnesses:

W. A. ALEXANDER, ELIZABETH BAILEY. 

